1. Field of the Invention
The present invention relates to the improvement of a winding apparatus for winding a sheet-like element, such as a tonneau cover for closing a rear cargo room of an automobile, and a sunshade for covering the door glass of an automobile.
2. Description of the Related Art
One such conventional winding apparatus is disclosed in JP-59-185148U.
This conventional winding apparatus was developed for winding a tonneau cover of an automobile. Although not shown concretely, this conventional winding apparatus consists mainly of an accommodating case fixed to a rear-cargo-room-side portion of an automobile, a winding shaft, disposed in this accommodating case, for winding a tonneau cover, pushing means for rotating and pushing this winding shaft in a winding direction in which the tonneau cover is wound therearound, and a spring member serving as a damping means to be brought into elastic contact with a surface of the tonneau cover to be wound around the winding shaft.
Therefore, when an end portion of the tonneau cover is drawn from an opening in the accommodating case in which the winding shaft is disposed, the tonneau cover is gradually drawn therefrom against the turning/pushing force of the aforementioned pushing means. Then, the end portion of the tonneau cover is caught at a backpanel-side portion facing a back seat. This enables the closing of the rear cargo room. Conversely, when the state, in which the end portion of the tonneau cover is caught at the backpanel-side portion, is canceled, the tonneau cover is automatically wound around the winding shaft this time by the turning/pushing force of the pushing means. Near the end of this winding operation, the aforementioned spring member comes into elastic contact with the surface of the tonneau cover. Thus, the spring member provides a damping force thereto so as to damp the winding speed of the winding apparatus. Consequently, the tonneau cover is slowly wound by the winding apparatus. Hence, the end portion of the tonneau cover is prevented from strongly hitting an opening edge of the accommodating case and producing impact sounds, and from being damaged.
However, when the conventional winding apparatus is in a state in which the tonneau cover is once drawn out and in which the rear cargo room is closed, the diameter of the outer peripheral portion of the winding shaft is reduced by an amount corresponding to a drawn-out part of the tonneau cover. Thus, the aforementioned spring member serving as the damping means does not act. Conversely, in the case that the tonneau cover is initially drawn out, the diameter of the outer peripheral portion of the winding shaft is larger than that in the state, in which the tonneau cover is drawn out, by an amount corresponding to a wound part of the tonneau cover. Thus, at that time, the damping force of the spring member acts thereon, so that an excessive force is required for drawing out the tonneau cover. Consequently, it is incontrovertible that the feeling of use thereof is deteriorated.
The invention is developed to effectively solve the problems of the conventional winding apparatus. According to the invention, there is provided a sheet-like element winding apparatus (hereunder referred to as a first winding apparatus of the invention) having an accommodating case, at one end portion of which a cap is attached to, and also having a winding shaft, disposed in the accommodating case, for winding a sheet-like element, and a pushing means for rotating and pushing the winding shaft in a direction in which the sheet-like element is wound. The first winding apparatus comprises a clutch mechanism provided at an end portion of the winding shaft. When a sheet-like element is wound, the winding shaft is connected through the clutch mechanism to a damping means for providing a damping force to the winding shaft. When a sheet-like element is drawn out, the connection between the winding shaft and the damping means is canceled through the clutch mechanism.
According to an embodiment (hereunder referred to as a second winding apparatus of the invention) of the first winding apparatus of the invention, the damping means is an oil damper.
According to an embodiment (hereunder referred to as a third winding apparatus of the invention) of the first winding apparatus of the invention, the damping means is an air damper.
According to an embodiment (hereunder referred to as a fourth winding apparatus of the invention) of the second winding apparatus of the invention, a shaft portion is provided in the cap attached to the one end portion of the accommodating case. Further, an insertion hole, into which the shaft portion is inserted, is provided in an inner-member-side portion of the oil damper.
According to an embodiment (hereunder referred to as a fifth winding apparatus of the invention) of the first winding apparatus of the invention, the clutch mechanism has two clutch surfaces to be press-contacted with each other. Further, one of the clutch surfaces is held in such a way as to be able to move in a direction of an axis of the winding shaft, and as to be unable to move in a circumferential direction thereof. Furthermore, projections are provided on an outer periphery of the one of the clutch surfaces. Moreover, a threaded surface is formed on an inner periphery of the accommodating case or the cap. Further, the projections and the threaded surface are screwed.
According to an embodiment (hereunder referred to as a sixth winding apparatus of the invention) of the third winding apparatus of the invention, a shaft portion is provided in the cap attached to the one end portion of the accommodating case. Further, an insertion hole, into which the shaft portion is inserted, is provided in a piston-side portion of the air damper. Moreover, an engaging portion is provided between the insertion hole and the shaft portion.
According to an embodiment (hereunder referred to as a seventh winding apparatus of the invention) of the fifth winding apparatus of the invention, opposed ratchet-like teeth are provided in a row in a circumferential direction on each of two press-contacted clutch surfaces of the clutch mechanism.
Thus, according to the first winding apparatus of the invention, when the sheet-like element is wound, the winding shaft and the damping means are connected to each other through the clutch mechanism. Thus, similarly as the case of the conventional winding apparatus, the sheet-like element is slowly wound around the winding shaft. Conversely, when the sheet-like element is drawn out, the connection between the winding shaft and the damping means is canceled through the clutch mechanism. Thus, the sheet-like element can smoothly be drawn out with a small force and without receiving the damping force of the damping means.
According to the second and third winding apparatuses of the invention, an oil damper or an air damper is used as the damping means, so that a nearly constant damping force is obtained and that the setting of the damping force is facilitated, whereas the conventional winding apparatus employs a simple spring member, so that as it becomes closer to the end of an operation of winding the sheet-like element, the damping force increases, and that sometimes, the sheet-like element is not completely wound.
According to the fourth winding apparatus of the invention, the oil damper is simply attached to the cap side portion only by inserting the haft portion provided in the cap into the insertion hole provided in the inner member of the oil damper. Thus, an assembling operation is facilitated. According to the fifth winding apparatus of the invention, one of the clutch surfaces of the clutch mechanism is press-contacted with the other clutch surface thereof with the progress of the screwing of the projection and the threaded surface, so that the winding shaft and the damping means are connected to ea other. Thus, when the sheet-like element is wound, the damping force can be provided only when the winding is finished.
According to the sixth winding apparatus of the invention, the air damper is attached to the cap side portion only by inserting the shaft portion, which is provided in the cap, into the insertion hole provided in the piston of the air damper. Thus, the assembling operation is facilitated. Moreover, the moving range of the piston can be restrained by the presence of the engaging portion. According to the seventh winding apparatus of the invention, the ratchet-like teeth are provided on the two press-contacted clutch surfaces of the clutch mechanism in the circumferential direction, so that the connection between the winding shaft and the damping means is reliably established and canceled.